Apparatus for use in the laying of antiaircraft guns



-A P... GR/ A APFARATUS FOR USE IN THE LA'ING OF ANTIAIRCRAFT GUNS .l I Filed-NovfZS, i953? ATTORNEYS ai.' -Apr K.

"k Lu P. w. GRAY APliTus 'Fok USE 1N was LAYING Ammcnxn vmms Filed Nav. 28. 1.922V

f 2 vshams-Smm 2 INVENTOR ATT'RNEYS tantas' arras stares maar .reina v AJ?? A.RATUS FOR USE IN THE LAYING OF ANTIAIRCRAFTG'UNS Application-mea Nvemher'as, 1522, serial Naeiiasss, andV in Great Britain December 22,-1921.'

T his' invention relates to apparatus for use in the laying of anti-aircraftlguns and is particularly"devised to obviate the errors which occur with known apparatus in determining or predicting the future position oi an'aerial target travelling-at a changing height. For example in the case of a target travelling along the line ot' sight of the apparatus it will be apparent that the angle of sight remains unchanged so that with apparatus Whose operation' is based on therate ot change of this angle, as has heretofore been the case, a false reading or'prediction will be obtained ot' the future position ot the target after the lapse of a given interval otl time in fact in the example referred to such apparatus would indicate that lthe tar- Cab of the future position of the target after the'v get is stationary.v Another example is that of a target travelling along anascending or descendinecourse (other. than a course at ninet;7 degrees to the line of sight) such that .the angle of sight-remains constant at all positions ot the target though the latter is not travelling along the line of-sight as in the previous example. In this case the target will be observed to change its angle of bearing at a certain-ratev andapparatus as heretofore proposed and used would, since there is no change in the angle of sight` operate on the false va'ssuinptioi'i that the target is travellingu long,- Vtlj'ie Vare of a circlepstruclt' from a point situated vertically' above the apparatus at a height equal tothe assumed constant height ol' the target. It will therefore he seen that in this example also there vvill be obtained a. false readinfr or prediction lapse oi" a. given interval of time. T he tivo examples given are extreme. cases but similar errors occur in all instances where the target is not travellingat a-c'onstant height.V

The primar;v object of the invention is to provide an apparatus lwhich avoids the errors referred to above.

In order-*that the said invention may he more clearly understood and readily'carried into effect, the vsaine Will be more fully described ivith'reterencc to the accompanying drawings Vin which.:

Figure l' is a"vi1eiv' showingYdiagrammatically a forni ot' apparatus in accordance with :PIE-:RCT WILLIS GRAY, OF WESTMDTSTER, LONDON, ENGLAND, ASSIGOR TO VICKERS y LIMITED, OF WESTMIN-STER, LONDONTELSTGLKNE, Y

this invention, it being understood thatto facilita-te the illustration the various parts are shown in positions which they would not occupy 1n actual practice,

Figure 2 is a plan showing a constructional form ot the apparatus mounted on or combined with an anti-aircraft rangetinder, and' Figure 3 is'a plan showing certain portions ofthe mechanism hereinafter,referred to'.

A. is the rangeiinder combine'd'ivith a casin; A1 (Figure 2) carrying the mechanism to be hereinafter described. This casing and the rangetinder are mounted on a carriage which is capable of being trained and which hastivo. seats A2, A3 tor the training operator and the elevating operator of the rang'etinder. The numerals l, 2, S. 4f and 5 in Figure 2 represent the positions occupied by 'the elevation correcting operator. the height following operator, the time of iiight sett-ing operator, the

predicted hearing following operator and thev rate setting operator respectively. -The duties performed by these operators will be apparent trom the ensuing description of the mechanism.

Z) is a crang pin which is adjusted in accordance with the estimated cou se and speed of the target in the horizontal plane, the adjustment for course being eected by a handle B which operates a Worm bo'meshing with a c'eiving' a block Zio" carrying the pin 7). The adjustment lfor speedis ei'ected by the angular displacement o't a disc B1 by Ameans ot' a milled head or knob carried thereby, this dis-:e carrying a bevelpinion 60x meshing with a vbevel'pini-.onv B0X ou a screw B00 'enga fing with the block v50": thus rotation of the'disc B1 adthe Wind does not'atect-the speedand direc- 100- i' -Worm Yc'heel 'B0 carrying a curse dial-'BKHU Figure 2) and having a radial guide for relao the rate of. changeof; linear deflection.

tion of travel of the target. Another crank pin c similarly adjustable by a handle C (op- Y erating adial CX) and a disc@1 in accordance With the direction and velocity of the Wind operates two further slotted members (l2-C3 of which the former thus receives a movement proportional to the rateof 'change of horizontal range and the other a movement proportional to the rate of change of deflection on the assumption that the target is merely `moving1withl andV atV the same" velocity as the Wind. These course and speed and Wind de-V similarly the movementsof the two members B3, C3 appertaining to the rates of change of deflection are added together by epicyclic gearing D to impart movement to another memberD1 in accordance with the resultant of these rates, that is to say in'accordance With The members R1 and D1 moving in accordance with the said resultante serve to vary the position of the movable elements or balls 7"v and d@ of the variable speed mechanism of range and bearing vclocks R0, Do driven by a constant speed motorV R09 byineans of which change of horizontal range and change of bearing are continuously obtained and given to shafts R2 and D2 respectively. This is performed in respect to vshaft R2 by means of the frictional driving connection of its cylinder '111 with the constant speed disc 1" of constant speed motor R00 through balls 9' Which are'movable into an infinite number of radial positions on disc Tof by member 'R1 to obtain proportional driving speeds for shaft R2 in the manner described. Shaft D2 is driven in the same Way by the frictional driving connection of its attached cylinder (ll with the constant disc T02 of speed motor R00 through balls Z0 which are adjustable radially on disc 702 bv member (ZO. The member d carrying the balls (Z0 is preferably operated from Thehandles Bl, C and the discs B1, C1 are ad,-Y

j'usted by the aforesaid rate setting operator by the so designed as -to impart "a movement"toA a' toothed sector R7 proportional to the logarithm of the instantaneous range. Another InA cam E designed to impart a movementv to a toothed sector El in accordance With the logarithm of the tangent of the angles of elevation of the rangender (which angles are the present angles of sight of the target) is operated by -a shaft 'E3 fromthe elevating handlel of the rangefinder and the movements of the said sectors RT and El are added together by an epicyclic gear e to operate a pointer H in accordance with the sum of the tvvo movements. Since thel tangent of the angle Y:of elevation is the height ofthetarget v divided by the horizontal range, the height is the product of the tangent of said angle and the horizontal range, or stated loga'rithniically log height equals log tan angle of elevation ,pluslog horizontal range. The movements of the pointerv H are thus in accru-dance with the logarithms of the height of the target Which can beread by the position of the pointer H against graduations on a height dial H1. Although, as stated above, the initial horizontal range is set on the mechanism by means .of the-handle R* this range need not be indicated since it is Converted into height before any indication is obtained. A second pointer H2 operated byasha'ft H in accordance With' the logarithm-s ofthe height as ascertained by the rangefinder is mounted co--axially with the other pointer H. Thus if the pointer H does not maintain coincidence tvith the pointer H2 this is an indication that the settings of the aforesaid pins@ and c require correction. instead of this follow-the-pointer arrangement, a balanced pointer may be employed, this single pointer being under the conjoint influence of a part moved ina similar-manner to the pointer H and of the shaft H3. through the intermediary of an epicyclic gear, the said single pointer remaining stationary opposite a fixed mark so long as the height derived as aforesaid fromthe range given by the range clocl: and from the angle of sight, corresponds to the height-as ascertained by the rangender.

The setting of the aforesaid pins' b and c can be furthermore checked from a coinparison of the angles of training of the rangelinder-obtained from the movements of Vthe training handle T"V andthe angles of bearing obtained fromV thenforesaid'bear- 235; met; a La@ tl e/ effect of thewind on the shot in a .similarz ing clock D0 for which purpose a followthe-pointer or balanced pointer arrangement similar to that above described may be employed. In Figures l` and 2 a balanced pointer BX? underV the conjoint influence.

( through a differential gear T01) of the shaft l)rl of the bearing clock and of the training handle T0 of the rangelinder is shown.

The .aforesaid member R1 moving proportionately to the total rate of change of range A. should preferablybe corrected for the range etl'ect ofY thewind on the shot. The correction for this Wind effect is represented by the product of the Wind velocity and a function ofthe time of flight-ofthe shotgthis func-*ries'a Vslider Z1 havinga'pin Z3 Which-enf8GV tion is obtained empirically and varies with guns of different caliber. To obtain this correction the epicyclic gear pinions B02 and C02 with which rack teeth von the members B2, C2 engage, are made of slightly different diameters in a predetermined ratio corresponding to the aforesaid function. The aforesaid member D1 moving proportionately to the total rate of change of linear detle'ction is also 'corrected for the deflection manner7 the epicyclic gear pinions B03 and G03 which engage rack teeth on the members B0 and G3 being also made of slightly different diameters. It Will,V of course, be understood that if the aforesaid function is unity, the pinions B02 and C02 would be'of the same diameter as would also the pinions B3 and G0. The movements of the members R1 and DL are arranged4 to be mechanically multiplied by the time of flight of the shot so. as to produce the change of horizontal range and the change of deflection of thetarget during the time of flight of the shot. F or this purpose the member R1 has a pin r engaging in a slot in a bar r1 which is pivoted at r to a fixed part and on which is mounted a slider T0 having a pin r3 engaging in slots formed at right angles to each other in members f, 7"* which are constrained to move in directions at right angles to their slots. The member f is set'at a distance from the pivot of the bar 'r1 proportionate to the time of flight, by a screw-threaded shaft f1 which. engages'in a nut f? formed on'the member and Which is rotated by a shaft fi* from a handle 7'* hereinafter referred to. The distance thatthe member r* is thus caused to assume from the axis oft-he pivoted arm r1 thus represents the product 'of the rate of change of range and the time of flight of the shot, that is to say it.. represents the change of range that takesplace during the time of flight of the shot. The movements of the said member 1* and those. of a shaft Rx moving inv accordance with the instantaneous range (it may move with the aforesaid cam R0 for example) are added together by an epicyclic gear indicated at 1 .and the algebraic sum of thesemovements is imparted by the equal to the algebraic sumof the instanta- .70

neous range and the change of range during the time of flight, that is to say .in accordance with the future or predicted horizont-al range.'

The aforesaid member l)1 moving in accordance with the total vrate of change of deflection corrected .for the dellection effectv 'ofthe Wind 'on the shot, operates'a'm'e-mber D01 .which has a pin d engaging in a slot in a pivoted arm d1. This pivoted arm cargages in a slot formed in amember (Zt and in a slot formed in a member 7*, these slots vbeing arranged at right angles to each lother and the members (Zt, fbeing constrained to move in directions at right angles to their slots. 'To prevent confusion the member cl* has not been shownin Figure 3. The said member fx' is operated'from. the afore said time of flight of shot shaft f3 by a screwthreaded shaft f engaging with a nut por- .fQi.1. 7' etthis member.

seen that the member d* will receive a displacement proportional to the product of the rate of change ofv linear deflection and the time of fiightofthe shot that is to say pro? v portional'to the linear deflection that takes It 'will thus be o. s

placemduring the time of flight of the shot.

for convenience of representation, in the slot in the member and a slot in a member 1'0* moving with the member di) is a pin P the Vposition of which thus determines thefuture or predicted 'position of the targetV when projected on to ahorizontal plan-e. The said pin P is attached to. a member Pr which is slidably mounted on a bar Pb pivoted by means of a spindle P51 to a fixed art. The said bar is thus angularly displaced by the pin P in accordance with the angle of predicted or future liiearing (ij-c.

the lateral angular deflection) of the target i and actuates a pointer P52 moving overa graduated dial P213. Arranged coaxially with the pointer P52 is a follower pointer Pot operated by a handle PB. The movev ments of this handlein causing the follower pointer Pb* to .follow the movements of the pointer P52 are added by an epicyclic gear indicated at T to the movements of a shaft T1 operated. by the handle T" in training the rangelinder and the sum of these movements.-

is imparted by the said epicyclic gear' to av transmitter switch PT by which the future angle of training or bearing with reference to a fixed line of reference is transmitted to the guns. The shaft T1' also operates to drive the dial Pbg so as to indicate in'conjunction with the pointer Pb2 the angles transmitted Y by the switch PT.

The above-mentioned shaft r moving in accordance with the predicted or future horizontal range operates to displace two pointers PR?, PR, which will be hereinafter referred to, in accordance with the predicted range.

The movement of the aforesaid shaft f3 inA accordance with the timewoftlight, of the shotV is obtained in the following mannerz-A drum F iseiigraved with curves so drawn that the angle of rotation of the drum is proportional to the time of flight of the shot corresponding to the-height reading on 'the'- displace the pointer PR: fromV its original position thus altering the height reading on the drum F which then has to be moved to keep the height in agreement with that indicated on the height drum Ht. Thus each of the factors (i. e. time ot' flight of shot and predicted range) is corrected by the other until a balancetLs-tate is obtained when the.A

hitting horizontal range and its corresikiond4 ing time of flight are arrived at. Thehaudle f* operates a transmitter switch f5 for transmitting the time of flight of the shot to the run or O'unsfor the ur ose of fuse set-l g C) ting, continuous fuse setting being .preferably employed so that there is no time lag to betalten into account.

Two of the aforesaid height drums Ht are provided and are operated ov means of a cam H* actuated from the shaft H3 in accordance with the movements of the aforesaid logarithmic height pointer H2 so as to permit evenly spaced graduations on these drums to ybe provided. The pointers 71.", Y ii appcrtaining to there drums are made adjustable in accordance. with the change of height during the time of tiight ot' the shot so that the drums Ht, H* indicate the future height of the target; for this purpose a multiplying mechanism is provided whereby the time of i tiight of the shotV multiplied h v the rate of change of height set on a dial r, this mechanism comprising a slotted member /LO displaced by the handle fi a slotted member H carrying the poii'iters lit. 7i." and a pivoted bar H01 carrying a sliding block L' having a pin engaging in the slots of the members linand HUK, this vbar being operated from a shaft hof apl'iertaining to the dial hx. Thus the pointers h4, li* are displaced by the said mechanism in accordance with the product of the time of vflight of the shot and corresponding to the rate of change of height V set on the dial i is continuously obtained and imparted to a shaft io. The movement' of this' shaft is added Vby anv epicyclic gear EIO to the Amovement of a shaft vliu by a handle 7L in accordance with initial height and a pointer HX is moved by mechanism incl-udingV a shaft Hu in'accor'd'ance'with the sum thus obtained after conversionby a cam ho* into logarithmic height. This pointer' is mounted Vcoaxially with the aforesaid pointers H, H2 and-the arrangement is such that if the rate of change of height is correctly set on the dial' 71."L the pointer HK will move in alignment with the follower pointer H. This arrangement thus constitutes a means of checking that the rate of change of height has been correctly set on the dial if.

llhe aforesaid predicted range pointer FR3 moves over a drum Ex engraved with curves so drawn that the angle of rotation of the drinn is proportional tothe quadrant elevation or gun elevation angle corresponding to the height reading on the drum. This rotation of the drum may be etfected through an epicyclic gear 6X the primary elements of which are driven one by a shaft e1 operated from the shaft and the handle E by the elevating operator of the rangeliiider in ele` vating the latter and the other by a handle (1': operated by the elevation correcting operator occupying the position indicated by theY numeral l in Figure 2. The third ele` ment of the epicyclic gear as well as driv ing the drum EK, also operates a transmitting switch El by means of which the correct tiring or quadrant elevation angle is transmitted to the gun or guns.

In operating the apparatus the lrate set ting operator occupying the position in Figure 2 sets wind direction and, estimated target course. on the dial CX and vBX by means of the handles C and B'respectively7 and then adjusts the dials C1 and B1 to correspond with the wind velocity and estimated target speed respectively. If the balanced bearing.r pointer Il is observed to be in motion, the rate setting operator occupying the position 5 first brin-gs it opposite a fixed index bx by means of a milled head attached to the pointer and then readjusts the target course and speed settings until the said pointer remains stationary against the fixed index.

The heightfollowing operator occupying the position 2 bringsthe follower pointer H by means of the handle R* into agreement with the height pointer H2 operated by the rangetaker. lf the follower' pointer H does:

izo

not follow automatically the height pointer H2 after being once brought into agreement; with the latter, the height following operatorpushes one of two electric switch buttons by means of which one of two lamp indicators c, b" Figure@ is lit sov as to inform the rate setting operator that an increase or decrease in the rate of change of range -is necessary, on which information the rate-setting operator readjusts the target course and speed settings whilst atthe Sametime keeping the bal` anced bearing 'pointerBL stationary against the fixed index t". Thus the correct rate of change of range and the correct,v rate of change-of linear deflection are set on the apparatus.

If the height following operator sees the second follower pointer HK (which is initially brought into agreement with the first follower pointer H by means ofthe handle ho) gradually moving away from the latter, he so adjusts the rate of change of height setting by means of a milled head attached to the dial h", as to obtain a constant agreement of the said'two follower pointers. A

The time of flight setting operator occupying the position 3 now turns his handle j until the predicted range pointer PE2 reads on the drum F the same height as that yindicated on the height drum PT* during which operation the pointer PE2 suffers a displacement on account ofthe fact that the setting ofthe time of flight of shot actuates the predicting mechanism by which the said pointer' is operated. This operation will also cause a displacementV of the height pointer h4 by an amount equal .to the change of height during the time of flight of shot, the indication now being the future heightinstead of the in stantaneous height of the target. Thus a continuous alteration of the time of flight of shot setting is needed until a balanced state is arrived at when the time of flight of shot corresponds to the future height and range of target and is then continuously transmitted to the gun by the transmitter f5.

The elevation correcting operator occupy-- ing the position 1 now rotateshis handle ei until the drum EX reads against the pointer Pfla the same height that indicated on the height drum H1, thus transmitting quadrant elevation angle to the gun by means of the switch Elx. I

The lateral deflection or predicted bearing following operator occupying the'posi-l The apparatus may comprise means for correcting the angle of bearing for drift. Tenuity corrections may be provided for by the use of different dials for gun elevation and tenuity conditions.

` What I claim and desire to secure by Letters Patent of the United Sta-tes is l. Apparatus for use in the laying of antiaircraft guns,. comprising elements v adjustable in accordance with the initial horizontal' range of a target, elements adjustable in ac-l cordance with the initial angle of bearingof the target, elements adjustable in accordance with the speed of the target inthe horizontal plane, elements adjustable in accordance position of the targetin accordance with windconditions. p Y

' 3. The combination with the elements claimedin claim-1, of means associated with the elements adjustable in accordance with the speed and course of the target and adj ustable in accordance with the rate of change of horizontal range and means for correcting the movement of said means in accordance with the effect of the wind on theshot. u

4. Apparatus for use in the laying of antiaircraft guns, comprising elements adjustable in accordance with the initial horizontal range of a target, elements adjustable in accordance with the speed of the target in the horizontal plane, elements adjustable in accordance with the course of the target in the. horizontal plane, means associated with the elements adjustable in accordance with the speed and course of the target and adjustable in accordance with the rate of change of horizontal range, means for correcting the movement of said means in accordance with the effect of the wind on'the shot.v means for multiplying the-corrected rate of change. of horizontal range by the time of flight of the shot, and a member movable by the last v 120 `aircraft guns, icomprising lelements adjustable in accordance with the initial horizontal range of a target, elements adjustable in accordance with the speed of the target in the horizontal plane, elements adjustable in ac-4 cordance with the course of the target in the horizontal plane, means associated with the elements adjustable in accordance with the for the time of flight of shot to suit different 70 i speed `and course of the target and adjustable in accordance with the rate of change of horizontal range,'meansv for correcting the movement of said means 1n accordance. 'with :he ei'fectof the Wind on the shot, means for Y accordance with the sum of the instantaneous horizontal range and the change of l1orizontal range for obtaining the predicted range.

7. Apparatus as in claim 5, Wherein the displacement of the part is multiplied by the displacement of a member' movable in accordance with the tangent of the angle of sight of the target and another member is displaced in accordance with the product in order to obtain the corresponding height of the target.

8. The combination with the elements claimed in claim 1, of means for determining the rate of change of the height of the target and for predicting the height after the lapse of a given interval of time.

9. The combination With the elements claimed in claim 1, of means associated with the elements adjustable in accordance with the initial angle of bearing of the target and adjustable in accordance lwith the rate of charge of linear deflection correctedY for the deflection eilect of the wind on the shot.

10. Apparatus for use in the laying of 'antiaircraft guns, comprising elements adjust ablein accordance with the initial horizontal range of a target, elements adjustable in accordance with the initial angle of bearing of the target, elements adjustable in accordance vrith the speed of the target in the horizontal plane, elements adjustable in accordance with the course of the target in the horizontal plane., elements adjustable in accordance with the height of thev target, means associated with the elements adjustable in accordance with the initial angle of bearing of the target and adjustable in accordance with the rate of change of linear deect'ion, means for correctingthe movement of said means in accordance with the effect of the Wind on the shot, means for multiplying the corrected rate of changeof linear deflection by the time of Hight of the shot, and a member movable by the last named means lin accordance with the change of deflection.

11. The combination with the elements claimed in claim 10. of means associated With theV member Vmovable in accordance with the change of deflection for obtaining the predicted angle of bearing.

12. Apparatus fornuse in laying anti-aircraft guns, comprising elements adjustable in accordance with the rate of change oftarget deflection, elements adjustable in accordance with the rate of change of range of the target, means for correcting the adjustment of the rate of change of range and deflection elements in accordance with wind direction and Velocity, means for determining the time.

of flight of the shot, means for'modifying the adjustment of the rate ofchange of deflection and range elements in accordance with the time of flight of the shot, elements Vadjustable in accordance with the rate of change of height ofthe target, means for combining the range and height of target values to obtain target elevation, and means for indicating target deflection and elevation as data for laying the guns 13. Apparatus as in claim' 12, including means for indicating'the time of flight of the shot. Y 14. Apparatus for use in laying anti-air 'craft guns, comprising a combined director sight and computing mechanism, said mechanism including a variable speed device having a part driven at constant speed, and another part at least partially adjustable by said sight, and means for indicating the values 'computed by said mechanism as data for laying the guns.

l5. Apparatus for use in laying anti-air craft guns, comprising a combined director sight and computing mechanism, means for 'adjusting said sight to follow` a moving aerial target, said computing mechanism-im cluding a variable speed device having a part driven at constant speed and an adjustable part, connections between said means and adjustable part, and means for indicating the values computed by said mechanismas data for the laying of the guns.

16. Apparatus for use in laying anti-aircraft guns, comprising a director sight, means for moving the sightto keep it on the aerial target, computing mechanism atleast" partially operated in accordance with the movements ofthe sight, said computer including a variable speed device having a part driven at constant speed, and means for indicating the values computed thereby as data for laying the guns.

17. Apparatus for use in laying anti-aircraft guns comprising a combined director sight and computing mechanism movable to follow the aerial target, said computer including a variable .speed device having a part driven at constant speed and a part at. least partially controlled by movementof the sight and computing mechanism, and means for indicating the computed values as data for laying the guns.

18. Apparatus for Ause in laying anti-airill) 19. Apparatus for use in laying anti-ain cra-ft guns, the combinationl of a movable director sight, a computing mechanism including means atleast partially cont-rolled by said sight for generating alinear quantity dependent upon the change in distanceot the target from the director, an indicator having a travelling member driven by said means,

a second travelling member associated with said first member 'for comparison therewith, and means for driving said second member in accordance with a linear quantity obtained for the observed distance .of the target.

Q0. Apparatus for laying anti-aircraft guns, comprising a movable director sight, a computing mechanism, connections between said sight and said. mechanism for introducing the relative vert-ical and lateral positions of the aerial target, means in said computer for determining vert-ical and lateral de'tlections, means for combining the vertical and lateral positions with the respective vertical and lateral deflections, and means 'for indicating these factors as dat-a for laying the guns.

21. Apparatus for laying anti-aircraft guns, comprising a movable director sight, a computing mechanism, connections between said sight and said mechanism for introducing the relative vertical and lateral positions of the aerial target, means in said computer for determining vertical and lateral deflections, means for combining the vertical and lateral positions with the respectivel vertical and lateral deflections, means for modifying vsaid factors in accordance with predetermined corrections, and means for indicating these :factors as data for laying the guns.

Apparatus for use in laying anti-air`- craft guns, comprising a sighting device, a variable speed device having-at least two parts, means for driving one part'of said variable speed device at constant speed, connections between the sighting vdevice and the other part. of said variable speed device for adjusting the latter in accordance with movements of the sight, means in said connections v for varying the movements of the sight received by said last named part 1n accordance with changes 1n the range of the target and windage, and means driven by said variable i speed device 'for indicatingvalues as data for laying the guns.

23. Apparatus for use in laying anti-aircraft guns, comprising a sight, a pair of variable speeddevices each having at least two parts of each of said devices at constant speed, connections between the sight and the other part of one of said devices, whereby -drivable parts, means for driving one of said the latter is adjusted in accordance with the movements of the sight in elevation, connections between the sight and the other part of lthe other of* said devices whereby the latter is adjusted in accordance with movements of the sight in train, meansin each connections for modifying the adjustment of the other parts of said devices in accordance with predetermined corrections, means driven by the first named device for-indicating cor. rected elevation as data for laying the guns in elevation,'and means driven by the otherv of said devices for indicating corrected train data for laying the guns 1n train.

- i releer-winnie saar; f 

